3-keto-20, 21-dihydroxy saturated pregnane compounds



Patented July 8, 1941 2 423 517 UNITED STATE PATENT OFFICES-KETO-ZMZl-DIHYDROXY SATURATED PREGNANE COMPOUNDS Tadeus Reichstein,Basel, Switzerland, assignor to the firm of Roche Orgonon, Inc., Nutley,N. J.

No Drawing. Original application February "i, 1941, Serial No. 377,915,now Patent No. 2,312,483, dated March 2, 1943. Divided and iliissqzzpplication January 27, 1943, Serial No.

' 1 mm. (Cl. zoo-391.4) l 2 This invention relates to compounds having aon H pregnane or pregnene skeleton, on. CH; l

on, em

I as illustrated, and having particular substituents H, 1 CH5 OH H atthe c3, c3. and C21 positions, those at the ca E ';-o-my1 and Cpositions being keto groups or hydroxyl 5 groups and those at the C11position being hydroxyl, acyloxyl or alkoxyl groups.

The following type formulas may be considered illustrative of thesecompounds:

0 H 20 0 cm CH| a OH on. cm on I 0 H 0H CH 0 H 1 J--O-Acyl H0 0 I on onO H a (B--(J-O-Acyl OH CH II E C-( J-0--Alkyl a o H 91 t: O-Alkyl CH:

CH CH 1]} 5 -OAcyl 14 OH OH E E OAlky1 U i H CH: CHI

Z Z-b-Am l: A I

on 11 cm on, & o Mky1 1, 3* h 18 on on E 5 at on o H i -(J-O-Acyl as 0 aCB: CHI g o Alkyl 22 on H 'J-!-OA07 I 1&

CH| OH;

In addition to the compounds specifically typifled by the above formulasnumerous other compounds varying in respects not important to thepresent invention are also included within the scope thereof. Forexample, the double bond of Formulas 13 to 24, inclusive, may be in the4-5 position rather than the 5-6 position as illustrated, or may be instill some other position, the only restriction being that it not be ina position which will interfere with the formation of the compounds bythe methods to be described.

Further, the compounds may contain more than one pair of double bonds,or may carry additional substituents attached to the nucleus, subject tothe same restriction that such additional double bonds or substituentsbe such as will not interfere with the reactions necessary to preparethe compounds, or can be added after formation of the compounds withoutdecomposing or otherwise disrupting them. Examples of substituents ofthe kind mentioned are additional hydroxyl, alkoxy, acyloxy and halogenradicals.

Compounds with a pregnane or pregnene skeleton have prior to the presenttime been isolated from natural sources or produced by oxydativedecomposition of higher molecular weight substances. The production ofderivatives of such substances substituted in the carbon atom C21 by ahalogen or by an oxy group such as an hydroxyl, an acyloxyl or analkoxyl group has not been described at all; Neither has the preparationof compounds of this type from lower molecular weight compounds such asthe etiocholenic or etiocholanic acids been described.

According to the present invention it has been discovered that compoundshaving a pregnane or pregnene skeleton, substituted at the Ca and C20positions by keto or hydroiwl groups and substituted at the C21 positionby halogen or an hydroxyl, acyloxyl or alkoxyl group can be preparedfrom the etiocholenic or etiocholanic acids. In general, the processcomprises converting the etiocholenic or etiocholanic acid into an acidhalide, reacting the acid halide with diazomethone and hydrolyzing toobtain a 20-keto, 21- hydroxyl compound having the desired skeleton.

When the starting material contains a substituent such as an hydroxylgroup or a keto group it is advantageous to protect this group duringthe reaction mentioned above and this may be done by converting it intoan acyloxyl or an alkoxyl group prior to the conversion of the compoundinto an acid halide.

By varying the conditions under which the acid halide is treated withdiazo-methane the resultant product may be caused to be either a21-diazo derivative or a 21-halogen derivative. Thus, if an excess ofdiazo-methane is present from the beginning of the reaction, as when thecholenic or cholanic acid chloride is poured into a solution ofdiam-methane, then the 21-diazo compound is formed, whereas if thediam-methan is added slowly to a solution of the cholenic or cholanicacid halide then a 21-halidecompound tends to be formed. The addition ofa hydrogen halide,

6 if desired after the protected groups in the ring system have beenreconstituted by alkaline saponification, 'will convert the 21-diazoderivatives into 21-ha1ogen derivatives.

Compounds of this type having a free hydroxyl group at the carbon atomCu maybe obtained by reacting the 21-diazo ketone with an oxygenousinorganic acid or with an organic sulphonic acid derivative. By reactionof the 21- diazo compounds with organic carbonic acids, derivativeshaving an acyloxy group at the carbon atom C21 may be obtained.

The 21-halogen derivatives may also be converted into 21-hydroxylderivatives by hydrolyzation with salts of weak organic or inorganicacids or converted into 21-acyloxy derivatives by reaction with organiccarbonic acids.

The 21-alkoxyl derivative may be prepared by alkoxylation in the usualway, before removing the protection from the substituents to thenucleus, this protection being subsequently removed by alkalinesaponification.

In order to give a clear understanding, the process and some of thenumerous variations will be formulated for a distinct simple case. As astarting material we choose 3-oxy-A5,6-aetiocholenic acid (Formula II).This acid or its derivatives acylated or alkoxylated in the hydroxylgroup can be prepared e. g. from stigmasterol or cholesterol. It is tobe understood that the following reactions are given by way of exampleonly and that the invention is not limited thereto.

- CH: CH:

OH; CH:

COCl

CH3 CH3 C 0-CHN2 on on oo-cmon on on co-omon CH: CH:

CO-OHzOR on. on,

(IQ-CHaHlE 3 on; on.

CO-GHaHlg It the free acid is used first the hydroxyl group is protectede. g. by acylation or alkoxylation; then the acid is converted into theacid halide (Formula 111). Upon reaction of the latter with diam-methaneeither the 21-diazo-ketone (IV) or the 21-halogen-ketone (D!) isobtained depending on whether from the beginning an excess ofdiazomethane is used or whether this is added in successive portions tothe acid halide. By careful alkaline hydrolysis the diazo ketone (IV) isconverted into the free hydroxyl-diazo ketone (V), provided the hydroxylgroup has been acylated and not alkoxylated.

By treatment of the diazo ketone (IV) with an aqueous o'xygenousinorganic acid, as e. g. suli'uric acid and phosphoric acids, or withorganic sulphonic acids, e. g. toluene sulfonic acid, eventually addingsuitable diluents, the derivative (V1) with a tree hydroxyl group in theside chain and a protected one in the ring system is obtained. On theother hand treatment of the oxydiazo ketone (V) with organic acidsappropriately in absence oi. water at temperatures ranging from about60-120" C. leads to derivatives of the Formula VlII, in which thehydroxyl group in the ring system is free and the one in the side chainis acylated. Analogous derivatives, in which the 21-hydroxyl-group isalkoxylized, the one in the ring system being tree, can be obtained from(VI) by alkoxylation, e g. with triphenyl methylchloride and subsequentalkaline saponiflcation. The derivative (VII) in which both hydroxylgroups are tree can be prepared either irom (V) with oxygenous acids orfrom (VI) by acid hydrolysis, hence it may also be obtained directlyfrom (IV) by prolonged treatment with e. g. warm aqueous sulfuric acidetc., eventually diluents being added. Treatment of (IV) with organicacids leads to diacyl derivatives with identical or different acylresidues; analogous derivatives can be obtained from VI, VII and VIIIbyacylation.

By treatment of (IV) with a hydrogen halide the corresponding halogenketone (IX) with a protected hydroxyl group are obtained. 11' thishydroxyl group had been acylated or alxokylated with alkyls which caneasily be eliminated the oxy-halogen ketone (X) can be prepared from(IX) by acid hydrolysis. This oxy-halogen ketone (X) is easily obtainedfrom (V) with a hydrogen halide.

The reactions mentioned can with the exception of the alkalinehydrolysis also be carried out after preceding saturation of the doublebond e. g. with bromine. All of them can be carried out in the presenceof diluents.

Analogous reactions may be carried out starting e. g. with thewell-known 3-oxy-aetio-allocholanic acid (Dalmer, Werder, Honigmann,Hayns, Ber. 68, 1814, 1936) and with other substituted derivatives oi.the aetio-cholanic or cholenic acids series carrying furthersubstituents in the ring system besides those at the carbon atom Caespecially oxygen as a hydroxyl group or in etheror oxide-like bonds.

Most of the derivatives of pregnanolone substituted in the carbon atomC21 are well crystallized compounds. If the substituent at the carbonatom C21 is a halogen, a hydroxyl or an acyloxyl group the substancesare very sensitive to alkalies and rapidly reduce an ammoniacal silversolution at ordinary temperatures.

Exmtrs For the sake oi. simplicity the examples will concern the casementioned above.

1. Production of diazo ketones The 3-oxy-aetio-cholenic acid or itsderivatives acylated or alkoxylated in the hydroxyl group used as astarting material can be obtained by oxydative decomposition of3-oxy-bisnor-cholenic acid (Femholz, Liebigs, Ann. 507, 128, 19 3) byway of a number of intermediate produc The free oxy-acid formscolourless crystals melting with decomposition at 280-288 C. (corrected)differences being observed at difierent velocities of heating. Itsmethylester iorms needles from benzene melting at 180 C. (corrected).The acylated acid melts at 240-.- 242 C. (corrected), its methylester at153-154 C. (corrected).

One g. of 3-acetoxy-aetio-cholenic acid is boiled with reflux for 3hours with 5 ml. of benzene and 5 g. of very pure thionyl chloride. Thenthe mixture is evaporated, humidity being excluded, upon which the acidchloride soon crystallizes. The weakly yellow product does not show adistinct melting point but decomposes at different temperature dependingon the velocity oi. heating.

Sometimes melting at 160 C. may be observed followed by resolidifyingand eventually melting again of the decomposed mass at a temperatureover 300 C. The chloride is dissolved in 80 ml. of dry ether and pouredinto a dry ethereal solution 01 1-1.5 g. of diazomethane, thetemperature being -10 C.

The mixture is left to stand for some hours at (2., then for 6 hours atroom temperature after which it is concentrated. Petroleumether is addeduntil a turbidity occurs. The diazo ketone crystallizes. From the motherliquor additional amounts are obtained in analogous ways. Yield 0.7 g.of a pure product, weakly, pale yellow leaflets, melting pointapproaching 150 C. somewhat diflerent depending on the velocity ofheating.

For the preparation of the free diam-21- preg-nene-5-ol-3-one-20, one g.of the above acetate is suspended in 30 ml. of methanol, 16 ml. of a 5%solution of potassium hydroxide in methanol are added and the mixture isleft to stand at room temperature for 6 hours with occasional agitation.The crystals dissolve after about half an hour. Then some water is addedand after concentration in vacuo the oxy-diazo ketone crystallizes. Itis filtered with suction washed with water and dried in vacuo; it can berecrystallized from ether-petroleumether, it then being obtained in paleyellow lustrous grains melting at 144 C. with vigorous decomposition;upon slow heating the melting point can be found lower. The yield isalmost quantitative. The product is distinguished from the acylateddiazo ketone by its being precipitated by digitonine from a 80-90%alcoholic solution.

2. Production of the halogen ketones 0.2 gram of the acetate ofdiazo-21-pregnene- 5-ol-3-one-20 is suspended or dissolved in ether andan ethereal solution of dry hydrochloric acid is added until the stormydevelopment of gas has finished. Then the ether and the excessivehydrochloric acid are evaporated in vacuo and the residue isrecrystallized from ether upon addition of pentane and subsequently frommethanol; the acetate of chloro-2l;-pregnene-5-ol-3-one-20 is obtainedin colourless needles with melting point 157-158 C. (corrected)CzaHasOsCl.

The same compound is obtained if at room temperature a solution ofdiazomethane is added drop by drop to an agitated solution ofacetoxyaetiocholenic acid chloride.

0.1 g. of the acetylated chloro-ketone is boiled with reflux for onehour with 2 ml. ethanol and 0.15 ml. concentrated aqueous hydrochloricacid,

its composition is,

the mixture is concentrated in vacuo and the 3. Production ofoxy-ketones with a free hudroryl group in the side chain 0.15 gram ofacetoxy-diazo ketone (Example 1) is dissolved in 2 ml. of dioxane; uponaddition of 1.5 ml. of 2 N sulfuric acid a production of gas beginswhich is completed by heating to about 40 C. The mixture is diluted withwater and extracted with ether; the ethereal solution is washed with asolution of sodium-carbonate, dried and evaporated to dryness in vacuo.For further purification the product can be sublimated in vacuo andrecrystallized from ether by concentration. In this way thepregnene-5-diol-3, 2l-one- 20-acetate-3 is obtained in colourless cystals which shows a correct composition (022113404) yet generally donot melt very sharply at about 150-155 C. Evidently they easily attractwater; the compound strongly reduces ammoniacal silver solution and isnot precipitated by digitonine.

To produce the free dioxy-ketone 0.1 g. of the above mono-acetate isdissolved in 2 ml. of methanol and boiled with reflux for one hour with2 ml. of water and 0.15 ml. of concentrated hydrochloric acid. Then themixture is evaporated to dryness in vacuo, the residue isdissolved in asmall quantity of acetone and precipitated by the additon of water,eventually sublimated in a high vacuum and recrystallized fromacetone-ether by concentration. The pregnene-5-diol-3, 2l-one-20 is thusobtained in colourless leaflets which may be clustered together and maycontain some solvent, the melting point generally not being verydistinct at 155-160 C. (corrected) notwithstanding the correctcomposition (Carl-1320a).

Often a second melting point can be observed.

The same compound is obtained from the oxydiazo' ketone (Example 1) withaqueous sulfuric acid. It reduces an ammoniacal silver solution and isprecipitated by digitonine.

4. Production of partially acylated oam-ketones with a free hydroxulgroup in the ring system (a) 0.2 g. of diazo-2l-pregnene-5-ol-3-one-20(Example 1) is heated for about 30 minutes at C. with 2 ml. of thepurest glacial acetic acid after which the production of gas isfinished. After cooling part of the acetoxy ketone crystallizes inbeautiful needles. It is suctioned oil and washed with ether-pentane.From the mother liquor the residual amount is obtained after evaporationin vacuo. The yield is 0.21 g. The needles contain solvent ofcrystallization: they become opaque near 80 C. and melt at 180-l82 C.(corrected). After eflective drying the composition is found to be thecalculated one (Ciel-B404). The compound is precipitated by digitonineand reduces an ammoniacal silver solution. The same compound can beobtained from the chloro-21-pregnenelone (Example 2) upon heating withpotassium acetate in ethanol or glacial acetic acid or with lead acetateand dioxane; however, this is not advantageous.

. (b) 0.1 g. of diazo-21-pregnene-5-ol-3-one-20 is dissolved in 0.5 ml.of dry dioxane by gentle heating and after addition of 0.25 g. ofbenzoic acid gradually further heated to -120 C. until the end of theevolution of gas, which takes about 25 minutes.

The further treatment consists of dissolution in ether washing withsodium-carbonate solution and water-drying and evaporating in vacuo. Theresidue crystallizes from methanol and is obtained by dissolving inacetone-methanol and subsequent concentration in spherical aggregated,which first melt unsharply near C.. then soon solidify to lustrousgrains to melt again at I'll-175 C. The composition corresponds to thepregnene-5-diol-3,21-one-20-benmate-21.

5. Derivatives partially alltocfllated in the side chain 0.1 g.oi-pregnene--diol-3,2l-one-20-acetate-3 (Example 341) is dissolved in0.25 mlaoi' pyridine and to it is added at 0 C. a solution ch75 mg. oftriphenyl-methyl chloride in 0.35 ml. oi benzene. The mixture is left tostand first one hour at 0 C. and subsequently two days at roomtemperature. Then it is poured into an aqueous solution orsodium-carbonate and shaken with ether. The ethereal solution is washedwith water dried and concentrated, residual pyridine being eliminated invacuo by gentle heating. The residual trityl compound, a thick syrupcontaining a little triform.

To saponify the acetou-group it phenyl-carbinol, can be treatedi'urtherina this is dissolved in methanol and upon addition or an excess of therconversions as well, e. g. oxidation of the,

hydroxyl group to a keto group (of. application Serial No. 195,162). g

The trityl compound hardly reduces an ammoniacal silver solution in thecold.

The compoundsabove described may be converted into compounds having aketo group at the 3-position by careful oxidation e. g. with chromicacid. In accordance with the principles of this invention it has beendiscovered that this may be done without ailecting or damaging thesensitive side chain despite the tact that these side chains areextremely sensitive to many oxidining agents, for example, being easilyoxidized in the side chain by a cold ammoniacal silver solutlon.

Special care is necessary it a double bond is present in the moleculeespecially one between the carbon atoms Cs and Ca as it is well knownthat in these cases the oxidation takes place in the double bond. Inthis case the double bond may be effectively protected according toknown methods e. g. by addition or a halogen ot a hydrogen hfllde andregeneration of the double bond after oxydation with simultaneousdisplacement or the double bond. Howeventhis treatment is onlyapplicable to those derivatives bearing a protected hydroxyl group atthe carbon atom Can. It a halogen is present at the carbon atom 021 theelimination of the halogen from the ring system would cause undesiredreactions in the side chain.

In the case of unsaturated derivatives with one double bond at thecarbon atom Ct the reaction can be carried out, simultaneously replacingthe halogen by a hydroxyl or an acyloxyl group, as follows: Afteraddition or a halogen and oxydation the product is heated with salts oiorganic or weak inorganic acids until the halogen in side chain has beenreplaced by a hydroxyl or an acyloml. Simultaneously one mol. ofhydrogen halide is eliminated from the ring'system, an unsaturatedmono-halogenated ketone thus bein produced. The halogen remainin at thecarbon atom C: can then be eliminated by reduction. This modification ofthe process is not particularly advantageous it derivatives substitutedat the carbon atom Cu with oxygenous groups to be prepared so that it.is then preferred. to start with derivatives bearing a protectedhydroxyl group at the carbon atom Cal. With-saturated derivatives,however, the. exchange 0!. a

halogen at the carbon atom Cu against a.hy-

meet with difllculties.

The polyketones with a tree hydroxyl grcun at the carbon atom Cal-areobtainedlbyjsaponlflcation of the corresponding derivatives with .ahydroxyl group whichhad beenacylated or alkoxylated with allavls whichcan be easily eliminated by hydrolysis or alkoholysis preferablyavoiding strongly alkaline agents although strong acids may be used inmost cases.- The hydroxyl-21"- ketones can also be prepared from thehalogen..- 21-ketones by the action of salts or organic or weakinorganic acids in the presence of water or alcohols. As stated above,however, thisis'only applicable to the saturated derivatives.

Afterwards the hydroxyl group at the carbon atom C21 can again beacylated or alkoxylized;

All or the reactions mentioned can appropriately be carried out in thepresence of solvents or diluents. Moreover it is unnecessary to separatethe compounds formed as intermediates. Th e., j200- ess will beelucidated by iormulationoi a simple case viz. the preparation 01'derivatives of mag"- nene-4-dione-3,20, substituted in. the carbon atomCal.

Aiterwards examples will be given for the preparation of the compoundsconcerned.

CH: CH;

(\ C OCH:O R

CH: CH: 0 0CH1O R I Br Br XII CH1 CH:

C O-CH1O Br Br XIII I CH: CH;

XIV

OHIO R CH; CH:

CHzOH CH] CH:

XVI

CHQHIK CH: CH!

XVII CHzHl CH; CH:

XVIII v CHzHl CH: CH:

l t. r

/ XIX CHiOAO CH: CH:

For example one starts with acetoxy-21-pregnene-5-ol-3-one-20 (FormulaXI, R=acetyl)'. Bromine is added whereupon the dibromide (XIII) isoxidized with oxidizing agents e. g. chromic acid whereby thedibromoketone (XIII) is formed. From this with reducing agents theunsaturated ketone (XIV) is formed which is converted by the action ofan acid with displacement of the double bond into the isomericunsaturated ketone (XV). Upon saponiflcation of this compound the freehydroxy diketone (XVI) is obtained. The way used for unsaturatedhalogen-zl-ketones is illustrated by Formulae XVII etc. After saturationof the double bond with bromine to obtain (XVIII) this is oxidized to(XIX) and by treatment with sodium acetate etc. this gives the ester ofthe unsaturated bromoketone of the probable Formula XX. From this thebromine atom can be removed with reducing agents, the diketone (XV,R=acyl) thus being formed.

In analogous ways the derivatives of pregnene with more than one freehydroxyl group in the ring system and halogen or a protected hydroxylgroup at the carbon atom C21 can be converted into the correspondingpolyketones. The compounds obtained will be used for the preparation ofmedicines.

Example 6 1 g. of acetoxy-21-pregnene-5-ol-3-one-20 (crystals with M. P.-182) (corrected) is dissolved in 5 ml. chloroform and to this is addeda solution of 0.45 g. of bromine in chloroform at 0 C. only the lastdrops causing a permanent yellow colour. Shortly afterwards the solutionis evaporated in vacuo, the residues being dissolved in a little.glacial acetic acid and to this a solution of 0.75 g, of chromic acid in30 ml. glacial acetic acid is added. The mixture is left to stand atroom temperature for 12 hours. Then it is poured into water and theprecipitating bromoketone is shaken out with ether. The etherealsolution is washed with some water, dried for a short period, and to itis added 2 g. of powdered zinc and 1 g. of water-free sodiumacetate. Theether is evaporated, shaking now and then, the temperature of the bathbeing 60 C. and the residue is heated at the same temperature withfrequent shaking for another 30 minutes, but at all events until asample poured in water and extracted with ether has become free ofbromine. Then the reaction mixture is taken up in ether, the solution isfiltered, washed with water and evaporated. The crystalline residue isheated for 5 to 10 minutes with glacial acetic acid until gentle boilingand thereafter evaporated to dryness in vacuo. For purification thecrystals can be sublimed in a high vacuum (a bath temperature of and apressure of 0.02 mm. gives with small amounts a sufficient velocity ofdistillation provided the heated surface is large enough) followed byrecrystallization from a small quantity of acetone, some petroleum etherbeing added.

Some 0.7 g. of pure acetoxy-21-pregnene-4- dione-3,20 are obtained ascolourless needles which upon heating become opaque near 60 C. and meltat 158-160" C. (corrected). After being well dried their composition isGail-13204. A solution in ethanol Or methanol rapidly reduces a coldammoniacal silver solution in the cold and its ultra-violet absorptionspectrum shows the band at about 240 m characteristic ofalphabeta-unsaturated ketones. The compound is ve y soluble in glacialacetic acid, ethanol, methanol, acetone, dioxane and benzene, to aconsiderable extent in ether and only difficultly soluble in petroleumether and water.

In the reduction with zinc one may heat more intensely from thebeginning whereby the subsequent treatment with glacial acetic acid toshift the double bond becomes unnecessary. Of course also other reducingagents can be used, so e. g. the debromination can be effected byheating same compound being formed. It ethanol is used as a'solvent theacetyl group at the carbon atom C21 is often partially saponifled, afree hydroxylgroup being formed. 01' course with the benzoate and otheresters as a starting material the reactionsproceed quite analogously.

Example 7 0.2 g. of the above acetoxy-21-pregnene-4- dione-3,20 isdissolved in 10 ml. of ethanol, 10 ml. of water and 1 ml. ofconcentrated hydrochloric acid are added after which the'mixture isboiled with reflux for 40 minutes. After cooling the solution isconcentrated in vacuo until beginning turbidity, after which it is leftto crystallize. The well-developed colourless crystals are filtered withsuction, washed with strongly diluted ethanol and then with water andfinally dried in the air. From the mother liquor the residual fractionis obtained by concentration.

Upon heating the crystals of pregnene-4-ol-21- dione-3,20 become opaquesomewhat. over 100C.

and melt at 137-439 C. After drying the com a small quantity of acetonewell developed, characteristic long needles are obtained which oftentake the form of triangles or of cut triangles. The compound can besublimated in a high vacuum without decomposition; at 0.02 mm. pressureand 190 bath temperature with a large heating surface the velocity ofdistillation is sufficient for small quantities.

It may be prepared in analogous ways from other esters and it can againbe converted into other esters whilst with alkoxylating agents nothaving strongly alkaline reaction the ethers can be obtained.

Example 8 0.3 g. of crude triphenylmethoxy-2l-pregnene- 5-ol-3-one-20 isdissolved in chloroform and treated with 0.08 g. of bromine inchloroform as described in Example 6.

After evaporation in vacuo the residue is dissolved without heating inthe required amount of slacial acetic acid and 0.15 g. of chromic acidin 7 ml. of glacial acetic acid are added.

After standing for 8 hours at room temperature the mixture is pouredinto water and shaken out with ether; the ethereal solution is washedwith water and dried over sodium sulfate, 0.5 g. of powdered zinc andsome sodium acetate are added, the ether is evaporated on a water bathand the residue after addition of some ethanol is heated for anotherhour on a boiling water bath whereby besides debromination alsodisplacement of the double bond and elimination of the triphenylmethylresidue from the molecul occurs. The ethanol is evaporated in vacuo,ether is added and the solution is filtered, washed with water andsodium carbonate solution, dried and evaporated. For completeelimination of the triphenylmethyl group the residue may be heated againwith aqueous ethanol and hydrochloric acid and thereupon evaporated todryness in vacuo. The triphenylcarbinol formed can then be eliminated bypartitioning the mixture between aqueous ethanol or about 50% methanoland petroleum ether. From the aqueous alcoholic solutions 16 thepregnene- 4-ol-21-dione-3,20 is obtained as describedinExample 7.

- Example 9 0.22 ,g. of chloro-21-pregnene-5-ol-3-one-20 (colourlessneedles; M. P. 162-464 C., corrected) is brominated in chloroform with0.108 g. of bromine and thereafter treated at room temperature with 0.2g. of. chromic acid, as described above. The mixture is poured intowater and shaken out with ether. The ethereal solution is washed withwater, dried and evaporatedat 50 C.

The residue is heated for several hours on a water bath with 3 ml. ofglacial acetic acid and 0.8 g. of water-free sodium acetate. Then 0.5 g.of powdered zinc is added and the heating is continued for about half anhour, depending on the quality of the zinc but at al1 events soloni thata sample poured into water and taken up in ether is practically free ofhalogen. Then the mixture is diluted with much ether, filtered. washedwith water and sodium carbonate solution and evaporated to dryness.Appropriately the residue is first distilled in a high vacuum followedby absorption e. g. on active aluminum oxide from benzene-petrolethersolution and elution with ether and acetone. Finally the product isrecrystallized as described in Example 1. The crystals formed areidentical with those described there.

For the reaction of saturated halogen-21-pregnane-derivatives withsodium acetate in glacial acetic acid, it is advantageous to heat tosomewhat higher temperatures, e. g. 3 hours at C.; then theacetoxy-2l-ketones are immediately obtained in pure form. However, withthe dibromo-derivatives it is better not to heat too intensely.

Compounds of the type described containing an hydroxyl group at the C20position may be prepared from "compounds containing a keto group atItheC20 carbon atom by carefully reducing the compound so that the carbonylgroup at C20 is converted into a hydroxyl group.

The resultant compound is a mixture oi two stereoisomers. This isomerismis due to the reduction of the carbonyl group. The two isomers also formtwo different acetal compounds. A separation of these two acetalcompounds may be eifected if desired by chromato-graphic analysis or byfractional crystallization.

For. example products having hydroxyl groups at each of the positions 3,20 and 21 may be prepared from compounds having either protected orunprotected hydroxyl groups at C: and/or Cu and a keto group at C20 bycareful reduction, e. g., with isopropyl alcohol and aluminumisopropylate, according to Meerwein-Pondorfl. If acyl derivatives areused as the starting material the reduction product must be saponifiedto reconvert the acyloxy radicals to hydroxyl radicals. In this waycompounds may be obtained having three hydroxyl groups at the 3, 20 and21 positions. To illustrate this latter process the following specificexample is given:

Erampl 1o Pregnene-5-diol-3.2Lone-20 or its derivatives acylated in thehydroxyl groups at Ca'and/or C21 are carefully reduced, e. 8-, withisopropyl alcohol and aluminium isopropylate, according toMeerwein-Pondorif. If acyl derivatives were used the reduction productmust further be saponified. In this way the free pregnene-5-trio-32021can 17 be obtained as a mixture of two isomers formin colourlesscrystals melting at 204-218.

A way of preparing compounds of the type herein described having a ketogroup at C: and hydroxyl groups at C20 and C21 comprises treating thetriol 3,20,21 compound with acetone to form a mono-acetone 20.21compound, and oxidizing to form a keto group at C3 and thereafterhydrolizing to free the hydroxyl groups at C20 and C21. The details ofthis process will be more clearly apparent from a consideration of thefollowing specific examples:

Example 11.Preparation of mono-acetone compound 570 mg. of trial weredissolved in 300 cm. of dry acetone and shaken for 6 days with 6 g. ofanhydrous copper sulfate. The copper sulfate was thereupon filtered oil,the solution was shaken with potassium carbonate and evaporated todryness. The crystalline residue was sublimated in a high vacuum (0.01mm. and 140-160"). A non-distillable residue remained. The sublimate wasrecrystallized from ether-pentane. was 355 mg. of crystals melting at146 (corrected), resolldifying upon further heating and melting again at166-169 (corrected).

(c.=2.737 in acetone).

The compound gives an intense yellow colour with nitro-methane showingthe presence of a double bond.

Example 12.Oa:idation of mono-acetone compound 375 mg. of themonoacetonepregnenetriol prepared according to Example 11 were dissolvedin 8 cm. of dry acetone and refluxed for 14 hours with a solution of 0.8g. of aluminium tertiary butylate in 30 cm. of benzene. Then the acetonewas removed, the solution taken up in ether and washed subsequently witha concentrated Seignette salt solution, sodium carbonate solution andwater. The washings were again extracted with ether and added to thebulk of the extract. The united ethereal extracts were then dried andevaporated leaving as a residue 550 mg. of a slightly yellow oil whichwas further fractionally distilled in a high vacuum the pressure being0.005 mm. Hg. At 50 bath temperature a first running came over which wasdiscarded. The bulk of the mass passed at about 170; its weight was 390mg.

Example 13.Fractination o monoacetone- 20.21-pregnene-4-one-3-diol-20.21

The product of Example 12 (390 mg.) was dissolved in cm. of pentane andfiltered through a column of 5 g. of aluminium oxide. The column waswashed twice with pentane which hardly eluted any material. Then thewashing was repeated twice with a mixture of 20% benzene and 80%pentane. Still the eluate contained only small amounts of solids whichwere worked up later together with the mother liquors remaining afterthe crystallization of the a-form.

Now the elution was continued with a mixture of equal parts of pentaneand benzene until practically no more solids were eluted. Uponevaporation the oxidation product crystallizes. The column was furtherwashed" with other which eluted 50 mg. ofunchanged'starting material.

The ketone fraction was recrystallized from 18 pentane whereby a partwas obtained as pure crystals melting at 124-125".

The lower melting and the syrupy components were now again subjected toa chromatographic separation whereupon the several eluates with 50%benzene-pentane were worked up separately. In all 245 mg. crystals ofthe a-form (M. P. 122 124) were obtained. After recrystallization frompentane the melting point rose to 126 (correct- The ield ed). (a)=+91.5-: (c.=2.252 in acetone).

The a-mono-acetone-pregnene-4-dioi-20.21- one-3 is easily soluble in allorganic solvents with the exception of petroleum other. In water it ispractically insoluble.

The mother liquors from the crystallization of the aform and thefraction which was obtained in the chromatographic separation only uponextraction with ether were united (180 mg.) and again refluxed with a 4cm. of acetone, 15 cmi of benzene and 0.4 mg. of aluminium tertiarybutylate and worked up as described above. The chromatographic analysisis also repeated as described above but now gave as the main product thep-form of the mono-acetone-pregnene-4-diol- 20.21-one-3. Whenrecrystallized from pentane it was obtained in colourless leafletsmelting at. 132 which gave a strong melting point depression with theu-form described above. Yield 70 mg. (a) "=+70.5i-1.5 (c.=1.701 inacetone).

Example 14.-Preparation of free pregnene-4- diol-20.21-0ne-3 dorm-235mg. of a-mono-acetone compound obtained according to Example 13 weredissolved in 8 cm. of ethanol and upon addition of 10 cm.-' of water and2.5 cm. of glacial acetic acid the solution was refluxed for 2 hours ona water bath. Then it was evaporated to dryness in vacuo whereupon thesame treatment was twice repeated. The crystalline residue so obtainedwas extracted five times with ether which dissolved it almostcompletely. Upon evaporation mg. of crystals melting at 166-176"(corrected) were obtained. (a) ==+92.6:1 (c.=1.932 in abs ethanol). Thesubstance is easily soluble in ethanol and acetone, difiicultly solublein ether and hardly soluble in petroleum ether.

p-,form.-This one was prepared from the corresponding acetone compoundin exactly the same way as the u-compound. The melting point, however,was 183185 (corrected). The mixed melting point of aand p-forms was138-155 (corrected) The new compounds as described and obtainablevaccording to this invention can be used as therapeutics or theintermediate products for the synthesis thereof. Y

This application is a division of my copending application Serial No.377,915, which in turn is a continuation-in-part of my copendingapplications Serial No. 195,161 filed March 10, 1938; Serial No. 195,162filed March 10, 1938; and Serial No. 250,025 filed January 9, 1939.

I claim: The compound CH: CH:

CHOH-CH2OH TADEUS REICHSTEIN.

